This invention is related to the art of orthodontics, and more particularly to the art of achieving proper alignment of the dental arch through forces applied to selected teeth by orthodontic applicances.
The practice of orthodontics is concerned not merely with the aesthetic alignment and appearance of teeth, but primarily addresses the proper positioning of teeth in relation to the bony structure of the face. For an individual facial structure, one can construct the optimum formation of the maxillary and mandibular arches, and the degree of an individual's orthodontic malformation can be related to the departure from those optima. In general, orthodontic practice seeks to realign teeth to form arches closely resembling the optimum shapes.
Because many patients exhibit dental "crowding"--the eruption of teeth in a portion of the arch too small to accomodate them naturally--conventional treatment regimes generally call for the extraction of four teeth (usually the first bicuspids) as an initial step. Those in the art justify this procedure by the requirement to allow sufficient space in which to realign the remaining teeth.
It has been found, however, that long term problems can stem from such extraction. First, relapse can occur, given the relatively long distances over which some teeth are moved within the arch. Second, such extractions can cause articulation problems, which may or may not be correctible by speech therapy. Finally, indications point to these extractions as a cause of temporal mandibular joint dysfunction later in life.
In the same manner that dentistry in general has attempted to eschew extraction except as an extreme measure, orthodontic practice should develop techniques that treat extraction as the exception rather than the rule. Such a technique forms the basis for the present invention.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a system of orthodontic appliances that can operate to increase space in a dental arch without extraction.
A further object of the invention is a method for increasing space in a dental arch without extraction.
Yet another object of the invention is a system of orthodontic appliances that combine the effects of a palatal expander bar, an extraoral force device, and a lip bumper, to provide arch expansion for both the maxillary and mandibular arches.
These and other objects are achieved in the present invention, which addresses both a system of orthodontic appliances and a method for their use. Increased space in the maxillary arch is gained by the use of a transpalatal bar. The transpalatal bar means includes adjustable palatal wire means, the ends of the palatal wire means being received in maxillary lingual sheaths carried on a pair of maxillary molars. The wire receiving portions of these lingual sheaths are mesially offset by about eight degrees. The mandibular expansion means includes lip bumper means extending around the periphery of the mandibular arch without making contact with the teeth thereof, with the distal ends of the lip bumper means being received into the bumper receiving portion of mandibular buccal tube means carried on two mandibular molars. The bumper receiving portions are mesially offset by about five degrees.
The system may further include extraoral force means, including headgear means for applying a specified force to selected teeth, with the distal ends thereof received into maxillary buccal tubes carried on two maxillary molars.
A method of gaining space in a dental arch according to the invention includes the steps of rotating and distally moving the first molars by application of a rotational and distal force through orthodontic appliances carried on a pair of molars. The rotating and moving force is transmitted to the molars through appliance receiving means having a mesial offset. Further distal movement may be obtained by the step of applying a distal force to the maxillary first molars by an extraoral force means. It should be noted that this method specifically does not include the step of extracting teeth in order to gain space within the arch.